The present invention relates to an aircraft panel design comprising an opening equipped with a surround.
The structure of an aircraft generally comprises several panels through which are made openings that are closed off by elements that may or may not be transparent.
FIG. 1 illustrates, in cross section, a known arrangement of the surround 10 of an opening 12 made in an aircraft fuselage panel 14 being fitted with a window 16.
Thus, according to this prior art, the surround 10 used to attach the window-pane 18/window-seal 20 assembly to the opening 12 consists of a single surround component 22 in the form of an angle section straddling the edge 24 of the opening 12.
More specifically, the base 26 of the component 22 has a heel 28 that fits into the opening 12, and a horizontal part 30 pressed against the edge 24 of the opening 12 and fixed to the panel 14.
The heel 28 then comprises a lip 34 extending towards the centre of the opening 12 to support the window-pane 18/window-seal 20 assembly, while a retaining device 33, that rests against a vertical extension 32 of the horizontal part 30, clamps the assembly from the other side.
In this prior-art design, the horizontal part 30 of the surround component 22 is fixed to the edge 24 of the opening 12 at numerous points, 70 to 100 points, to give a rough idea of scale, by piercing the panel and then riveting.
A first disadvantage with the design, in the case of a fuselage panel made of composite, is that the operations of drilling and counterboring the rivet holes are very awkward to perform near the edge 24 of the opening 12, especially in the case of a carbon-fibre-based composite.
Thus, because of the number of holes to be made for each opening 12 in an aircraft and because of the difficulty of performing the machining operations, the costs associated with fixing the surround components 22 for an aircraft are relatively high.
In addition, a second disadvantage is that the rivet holes and the number of them weaken the edge of the opening and impair the mechanical stability of the edge against deformations due to the flexing of the fuselage and to the cabin pressurizing forces.